Several proteins secreted by the placenta have been considered to be pregnancy-specific. This proposal will examine a variety of non-trophoblastic normal adult human tissues for the presence of four of these pregnancy-specific proteins--human chorionic gonadotropin, human chorionic somatomammotropin, pregnancy-specific-beta1-globulin and placental cystine aminopeptidase (oxytocinase). These proteins will be measured by specific immunoassays and where applicable, radioreceptor assays. Tissue extracts will be prepared by extraction in phosphate-buffered saline followed by ultracentrification and ultra-filtration. Serial dilutions of the extracts will be examined for parallelism in the various radioimmunoassays. In addition, the chromatographic behavior of the extracts on Sephadex columns and columns of concanavalin-A-Sepharose will be examined and compared to similar studies carried out with purified or partially purified preparations of these materials from placentas or pregnancy serum. The various labeled ligands that will be utilized in each of the immunoassays will be incubated with tissue extracts and chromatographed on the Sephadex and concanavalin-A-Sepharose columns in order to examine the possibility of enzymatic alterations of the ligand. An attempt will be made to purify any placental protein-like substances that are found in normal tissues by immunoadsorption of the placental protein to specific antisera that have been covalently coupled to Sepharose B.